wow (check your points!)

[j9fd3s]

so i pulled the distributor this morning to change the fuel injection trigger points, and while i was in there i noticed my ignition points were barely opening!

i cleaned the ignition points (with a $100 bill, nudge nudge, wink wink) set the gap to specs, and i think i found out why it only dynoed 140rwhp.

i also seem to have lost my fear of points....

mike

[300SDog]

Good idea using paper instead of a file to clean the points..... Tradition says that business card of somebody you hate works the best, if you dont have $100 bill handy.

And points lore also says that if you ever find them pitting on one side or another, then this indicates poor unballanced electrical flow that can be remedied with new condenser and/or ignition coil 'pigtail' grounding wire or something else.

Old sharpies who know points best can even tell you if it's positive or negative where the electrical leak might occur, based on which side of the points is getting pitted.

Fear of old style ignition points? They went out of style just because they were so SIMPLE. God Save the automobile from too many high tech "improvements".

[wbain5280]

Setting points is easy, loosen the distributor, turn it until the points are on a lobe, set the gap, turn the dist. back to the original position and tighten. Check the timing with a strobe light and the vacuum line detached. Don't forget to use blackboard chalk on the timing degrees on the harmonic balancer (easier to see).

[Tomguy]

Warren: I dont know about other engines but if he has a 3.5 or 4.5, he MUST set the timing with the vacuum connected. It's not like most American cars (were?)

[wbain5280]

OK< my mistake. Follow the service manual.

Cheers.

[300SDog]

Coolest thing about points - you get to check the adjustment with dwell/tach while the car is running so you can even hear the difference too.

Fiddling with ignition points twice each year strikes me as selling feature for the Vintage MB hobbyist who enjoys messing around under the hood.

When did MB opt for electronic ignition? My '73 280/8 had electronic 'lazer beam' ignition with rotating set of spikes that fired the sparkplugs. And did MB at one time produce dual point ignition systems in their V-8's?

I kinda miss the olden days of hooking up the dwell/tach and setting the points on my finbody cars. Am thinking among mechanical maintenance items that points are state of the art.

[j9fd3s]

Originally Posted by 240DieselDog

Coolest thing about points - you get to check the adjustment with dwell/tach while the car is running so you can even hear the difference too.

Fiddling with ignition points twice each year strikes me as selling feature for the Vintage MB hobbyist who enjoys messing around under the hood.

When did MB opt for electronic ignition? My '73 280/8 had electronic 'lazer beam' ignition with rotating set of spikes that fired the sparkplugs. And did MB at one time produce dual point ignition systems in their V-8's?

I kinda miss the olden days of hooking up the dwell/tach and setting the points on my finbody cars. Am thinking among mechanical maintenance items that points are state of the art.

i like these cars because you dont seem to have to replace that much stuff, most of it is saturday morning clean/reset/adjust to specs. which is nice

[psfred]

Several engines used dual point distributors ( M100 V8 and several sixes).

The points on the transistor ignitions (blue coil) must NEVER be cleaned with a file or anything abrasive, they are platinum plated and will die quickly if abrasively cleaned. They are a logic switch only, they do not operate the coil if the transistor box is working.

There is no gap spec for MB, they are set by measuring the dwell.

Benz started using the transistor switched system around 1970 (possibly earlier), and changed over to a breakerless (Hall effect trigger) sometime in the late 70s. Very positive change as far as I'm concerned, since the timing no moger varies with rubbing block wear.

Peter

[j9fd3s]

Originally Posted by psfred

There is no gap spec for MB, they are set by measuring the dwell.

Peter

the service manager at the dealership i work at used to be an mb tech in the late 70's early 80's, and he said .016" gap. my book says .3mm which is .012, this gave me a dwell in the 20's. .016 should be right on.

the other tip so far is to take the radiator out for everything, even the belts, which they would spin on. tricky

mike

[autozen]

There is an old saying. If you want to see a parts man smile, tell him the make, model, and year when you ask for parts. With little to go on here, Im assuming this is a Mercedes. Because of the mention of trigger points I'll venture another guess that this is a 71 3.5 or a 72-75 4.5. You can use paper to run through the points to clean the blue buildup, But I wouldn't use a treasury note, because it is dirty. I would use the FOLDED edge of a clean piece of white paper. If you use the ragged edge of a piece of paper, you run the risk of leaving paper fibers between the points. There is very little current flow through these points so it doesn't take much to muck them up. Also the condensor inside the dist is useless and creates more problems than if it weren't there. The smart thing to do if you haven't done it already is to snip the wire. There may be some gap specs somewhere, but I agree with PSFRED that setting dwell to 30* with a meter is the only way to go. I also wouldn't change the trigger points unless they had failed. They are expensive and just need the oil that travels up the distrib shaft cleaned out with carb cleaner. Spinning v belts on is a bad idea. It saves labor time but damages the belt. I don't think you can even do it anymore with the new style service free belt. It will probable break on install.


Peter